Kondorosi E, Buiré M, Cren M, Iyer N, Hoffmann B, Kondorosi A
Centre National de la Recherche Scientifique, Institut des Sciences Végétales, Gif-sur-Yvette, France.
Mol Microbiol. 1991 Dec;5(12):3035-48. doi: 10.1111/j.1365-2958.1991.tb01863.x.
We identified and sequenced the regulatory syrM and nodD3 genes of Rhizobium meliloti 41. Both genes were shown to contribute to optimal nodulation of alfalfa. In R. meliloti strains carrying syrM and nodD3 on plasmid, the nod genes are expressed constitutively, resulting in host-range extension to siratro. This is due to the presence of multiple syrM copies, suggesting that SyrM participates directly in nod gene activation. NodD3 activates nod genes in conjunction with flavonoids and enhances syrM expression, which is controlled also by its own product, NodD2, and two putative trans-acting factors. nodD3 is regulated by SyrM, NodD1, nodD3, the repressor NoIR, and two putative factors.
我们鉴定并测序了苜蓿根瘤菌41的调控基因syrM和nodD3。结果表明，这两个基因均有助于苜蓿的最佳结瘤。在携带syrM和nodD3的苜蓿根瘤菌质粒菌株中，结瘤基因组成型表达，导致宿主范围扩展到银合欢。这是由于存在多个syrM拷贝，表明SyrM直接参与结瘤基因的激活。NodD3与类黄酮共同激活结瘤基因，并增强syrM的表达，syrM的表达也受其自身产物NodD2以及两个假定的反式作用因子的控制。nodD3受SyrM、NodD1、nodD3、阻遏物NoIR以及两个假定因子的调控。
